01 - Preheat oven to 400°F. Line a baking sheet with parchment paper or lightly grease the surface.
02 - In a small bowl, combine garlic powder, paprika, salt, and black pepper. Set aside.
03 - Pat the chicken breasts dry. Using a sharp knife, cut a pocket into each breast, taking care not to slice all the way through.
04 - Rub each chicken breast with olive oil and coat generously with the prepared seasoning mix, ensuring the pocket interiors are seasoned.
05 - In a mixing bowl, combine finely chopped broccoli, shredded cheddar cheese, softened cream cheese, grated Parmesan, Dijon mustard, and minced garlic. Blend thoroughly.
06 - Fill each chicken breast with the broccoli-cheese mixture and secure with toothpicks if needed.
07 - Place the stuffed chicken breasts on the prepared baking sheet.
08 - Bake for 25 to 30 minutes, or until chicken is fully cooked (internal temperature should reach 165°F) and cheese is melted and bubbling.
09 - Allow the chicken to rest for 5 minutes. Remove toothpicks before serving hot.